Latch mechanism for die block of punch press



Dec. 6, 1966 D. L. PICCONE 3,289,519

LATCH MECHANISM FOR DIE BLOCK OF PUNCH PRESS Filed Dec. 14, 1964 2Sheets-Sheet l FIG-l INVENTOR.

/ DONATO L. PICCONE ATTORN EY Dec. 6, 1966 D. L. PICCONE 3,289,519

LATCH MECHANISM FOR DIE BLOCK OF PUNCH PRESS Filed Dec. 14, 1964 2Sheets-Sheet 8 TI IA H III 1 um. 3A

INVENTOR DONATO L. PICCONE ATTORNEY United States Patent 3,289,519 LATCHMECHANISM FOR DIE BLOCK 0F PUNCH PRESS Donato L. Piccone, 315 E.Williams, Ann Arbor, Mich. Filed Dec. 14, 1964, Ser. No. 418,018 Claims.(Cl. 83-685) This invention relates to punch and die mechanisms,particularly as used in punch presses.

Operation of a punch press commonly imposes heavy wear on the punch anddie, thus necessitating unduly frequent replacement of said parts toassure accurate shearing. Changes in shape and'size of openings to beformed in different types of work also occasionally require replacementsof dies and punches. Such. replacements have been laborious andtime-consuming and hence a source of considerable expense.

A primary object of the invention is to provide a simple and inexpensivemechanism whereby a die coacting with a punch may be readily and firmlylatched to or released from its retainer.

Another object is to provide a bolt for latching a die in a retainer bymeans of a plunger actuable in the die to establish and maintain theeffective position of said bolt, coacting cam faces being formed on theplunger and bolt for eifecting such actuation.

Another object is to employ a metal ball as a latch bolt for eithersecuring a die in its use position or releasing it to afford its readyremoval.

These and various other objects are attained as appears in theaccompanying drawings, wherein:

FIG. 1 is a fragmentary vertical axial sectional view of my improvedlatch mechanism as applied to a punch press, the latching position ofsuch mechanism being shown.

FIG. 2 is a similar sectional view of the latch mechanism, but showingits released position.

FIG. 3 is a vertical sectional detail of the latch mechanism, taken onthe line 3--3 of FIG. 2.

FIG. 4 is a view similar to FIG. 1, but illustrates another embodimentof the invention.

FIG. 5 is an enlarged fragmentary vertical sectional detail of themodification appearing in FIG. 4, and shows a released position of themechanism.

Describing first the invention as illustrated by FIGS. 1-3, thereference character 1 designates the usual punch of a punch-press, saidpunch being vertically reciprocatory to and from a cylindrical die 2.Adjoining its top face, the die 2 is formed with a circular aperture 3proportioned for shearing coaction with the punch. A workpieceexemplified at 4 and usually of sheet-metal is disposed across the diefor perforation by the punch. The die is formed with a frustoconicalpassage 5, downwardly extended from the aperture 3 and opening in thebottom face of the die to accommodate disks 6 struck out of the work bya punching operation. The die is proportioned to slide vertically withno material lateral motion in a cylindrical socket 7 formed in the dieretainer 8.

At one side of the passage 5 and aperture 3, a plunger 9 is verticallyslidable in a bore 10 formed in the die 2, and is upwardly urged by acoiled spring 11, occupying the bore beneath the plunger. A verticaladjusting screw 12, coaxial with the plunger, is threaded in the topportion of the bore 10, and has its lower end seated on the upper end ofthe plunger, such screw coacting with the spring 11 to regulate theup-and-down position of the plunger. Slidable in the die 2 radiallythereof is a latch bolt 13, the outer end of which is adapted to enter acircular groove 14 formed in and opening from the inner face of thesocket '7. A tensional coiled spring 15 is mounted on a stem 16extending rigidly inward from the bolt 13, said spring tending toestablish the inner limiting position of the bolt, in

3,289,519 Patented Dec. 6, 1966 which position the bolt is clear of theretainer 8. The circular form of the groove 14 serves to permit the boltto take effect regardless of any particular rotative relation betweenthe die and retainer. The plunger 9 is diametrically slotted at 17 toaccommodate the stem 16, whereby the plunger may undergo the desiredup-and-down travel without impediment by said stern and is held by thelatter from rotation. The plunger 9 has a notch 18 in its lower portion,and the upper end of said notch forms an inclined cam 19 coacting with asimilarly inclined cam 20 on the inner end of the bolt 13.

When the screw 12 downwardly actuates the plunger, as in FIG. 1, the camfaces interengage to shift the bolt outwardly to its latching positionby insertion of the bolt in the groove 14. Because of the mechanicaladvantage afforded by the screw, a considerable pressure may be readilyapplied to the bolt to maintain its latching position. When the screw 12permits the plunger to assume its raised position, as in FIG. 2, thespring 15 shifts the bolt 13 inwardly, disengaging the cams 19 and 20and permits ready upward removal of the die from its socket 7.Prevention of rotation of the plunger 9 is of importance in maintainingthe proper opposed and coacting relation between the cams 19 and 20.

Describing now the modification illustrated by FIGS. 4 and 5, thereference characters 1a8a correspond to the characters 1-8, as appliedto the first-described modification. Formed in the die 2a, at one sideof the passage 5a, is a bore 21 downwardly extended from the top face ofthe die and having its upper portion threaded to mesh with an adjustingscrew 22. Said screw is engageable at its upper end by a screw-driver(not shown), or is otherwise adapted for rotative actuation. At itslower end, said screw is integrally formed with a cam 23 of invertedconical form, said cam having point contact with a metal ball 24,rotatively set into a runway 25 formed in the die 2a and opening in theperipheral wall of said die. From such wall, the runway extends to andopens into the lower end of the bore 21. The runway has a slightdownward inclination in extending inwardly, so that the ball tends toroll of its own weight toward the inner end of the runway. Set rigidlyinto the intercommunicating ends of the bore 21 and runway 25, is anabutment 26 which limits inward travel of the ball 24, positioning thelatter fully within the die and so avoiding any latching effect. Thus,at its inner limit of travel, the ball allows free up-and-down actuationof the die, and the latter is readily removable from its socket 7a. Ifthe screw is downwardly adjusted to its lowermost position, as per FIG.4, the cam 23 displaces the ball up the inclined runway and at leastpartially into a circular groove 27 formed in the retainer 8aperipherally of the socket 7a. Thus, an adjustment of the screw to itslower limit may apply a considerable outward force to the ball toestablish and maintain its latching position, as best appears in FIG. 4.

What I claim is:

1. A punch and die mechanism comprising a punch reciprocatory up anddown, a die formed with a passage accommodating the punch and adaptedfor shearing coaction with the punch, a retainer having a socket whereinthe die is removably received, the peripheral face of the socket havinga recess formed in the peripheral face of the socket, a plunger slidablein substantially up and down travel in the die at one side of saidpassage, a bolt slidable in the die to have releasable engagement insaid recess to resist withdrawal of said die from said socket, theplunger and bolt having interengageable cam faces, retractable drivemeans to actuate the plunger in downward sliding travel whereby said camfaces urge said bolt into said releasable engagement, means yieldableurging said plunger in upward travel responsive to retraction of saiddrive means, and means to urge said bolt to slidably disengage from saidrecess consequent to said upward travel to afford.

withdrawal of said die from said socket.

2. A punch and die mechanism as set forth in claim 1, said yieldablemeans being a coiled spring applying upthrust to the plunger.

3. A punch and die mechanism as set forth in claim 1, said recess beinga substantially circular groove substantially concentric with thesocket.

4. A punch and die mechanism as set forth in claim 1, the plunger havinga slot elongated along the plunger axis, and a stem on the boltextending through said slot and resisting rotation of the plunger.

5. A punch and die mechanism comprising a reciprocatory punch, a dieformed with a passage accommodating the punch and adapted for shearingcoaction with the punch, a retainer having a socket wherein the die isremovably received, the peripheral face of the socket having a recess, aplunger movable in substantially up and down travel in the die, saidplunger forming at its lower end All a cam of inverted conical form, aball set into a runway formed in the die and opening from said recess tothe lower end of the plunger at a downward inclination, and means on thedie for actuating the plunger up and down and thereby disengaging orengaging the ball to shift the ball up or down the inclination of itsrunway to engage it in or disengage it from said recess, said runwaybeing formed with an abutment at its inner end limiting travel of theball down the runway, and thus maintaining proper engagement of the ballwith said cam.

References Cited by the Examiner UNITED STATES PATENTS 1,621,811 3/1927Richard et al 83-698 X 2,009,371 7/ 1935 Iunge 28753 2,364,401 12/ 1944Stellin 83698 X 2,737,056 3/ 1956 Baumgartner.

3,190,165 6/1965 Schott.

ANDREW R. JUHASZ, Primary Examiner.

1. A PUNCH AND DIE MECHANISM COMPRISING A PUNCH RECIPROCATORY UP ANDDOWN, A DIE FORMED WITH A PASSAGE ACCOMMODATING THE PUNCH AND ADAPTEDFOR SHEARING COACTION WITH THE PUNCH, A RETAINER HAVING A SOCKET WHEREINTHE DIE IS REMOVABLY RECEIVED, THE PERIPHERAL FACE ON THE SOCKET HAVINGA RECESS FROMED IN THE PERIPHERAL FACE OF THE SOCKET, A PLUNGER SLIDABLEIN SUBSTANTIALLY UP AND DOWN TRAVEL IN THE DIE AT ONE SIDE OF SAIDPASSAGE, A BOLT SLIDABLE IN THE DIE TO HAVE RELEASABLE ENGAGEMENT INSAID RECESS TO RESIST WITHDRAWAL OF SAID DIE FROM SAID SOCKET, THEPLUNGER AND BOLT HAVING INTERENGAGEABLE CAM FACES, RETRACTABLE DRIVEMEANS TO ACTUATE THE PLUNGER IN DOWNWARD SLIDING TRAVEL WHEREBY SAID CAMFACES URGE SAID BOLT INTO SAID RELEASABLE ENGAGEMENT, MEANS YIELDABLEURGING SAID PLUNGER IN UPWARD TRAVEL RESPONSIVE TO RETRACTION OF SAIDDRIVE MEANS, AND MEANS TO URGE SAID BOLT TO SLIDABLY DISENGAGE FROM SAIDRECESS CONSEQUENT TO SAID UPWARD TRAVEL TO AFFORD WITHDRAWAL OF SAID DIEFROM SAID SOCKET.